AHP Final Report

Summary Report and Recommendations of the Alberta Research Council

on the Research and Operations of the 1980 to 1985

Weather Modification Program

Executive Summary

The importance of agriculture to the Alberta economy and the heavy costs associated with hail damage and drought have focused attention on the use of weather modification techniques. Because agriculture contributes $3 billion to the provincial economy, adverse weather can be devastating. For example, during the period 1980 to 1985, average annual hail damage cost about $150 million. In addition, the 1985 drought cost farmers an estimated $650 million. The most common type of weather modification is cloud seeding, which involves injecting clouds with dry ice or silver iodide. Results of the last five years of research in the province lead to optimism about the use of cloud seeding to decrease hail and to increase rain and snow.

Research Results

A better understanding of the physical processes that produce hail has been gained by investigating the whole precipitation process right from the large-scale synoptic weather patterns associated with fronts and low pressure systems to the microscope precipitation processes that occur within a cloud. The current state of knowledge about the Alberta hailstorm has been demonstrated to be essentially correct.

Results from hailstorm seeding experiments indicate that cloud seeding can increase the number of potential hail embryos of (in some storms) can cause potential hail embryos to precipitate prematurely. Evidence has been found that there are more hailstones on the ground from operationally seeded storms, but more observations would be required to determine if the size of the hailstones is significantly changed.

Because of limitations in the measuring and observing facilities, research has not yet demonstrated that more hail embryos lead to smaller hailstones or that fewer embryos result in less hail on the ground.

Computer calculations suggest that cloud seeding decreases hail (by nine percent) and increases rain (by seven percent). Research based on analysis of crop damage suggests a decrease in the loss-to-risk ratio of it, could be due to other factors such as climate change of insurance practices rather than to cloud seeding.

These results give reason to be optimistic about suppressing hail in the most common types of storms.

Research also indicates that towering cumulus clouds can be made to rain by seeding, even when such clouds would not rain naturally. This is significant since towering cumulus clouds are just as prevalent in drought periods as they are in periods of normal rainfall.

Limited observations of snow clouds over the Rocky Mountains in southern Alberta imply that a potential exists for increasing mountain snowcap.

Based on a 20-year operating period, the capital and operating costs of a cloud seeding program in Alberta would be recovered if annual crop losses were reduced by about five percent. Given experimental evidence to date, this is a realistic goal. Rain and hail experiments could be easily combined, as aircraft radar, weather office assistance and other observational support are the same for both.

Recommendations

Of the three forms of weather modification considered, that is hail suppression, rain augmentation and snow increase, the hail problem is the most complex and difficult to solve, but substantial progress has been made and hail suppression looks feasible at least for some types of storms. It is recommended that hail suppression research receive continued support to address the questions that remain/ It is also recommended that continued analysis of the data obtained from the 1980 to 1985 program be supported to provide more definitive conclusions about the effectiveness of weather modification and to help focus future research efforts. Further experimentation is required and recommended to optimize the seeding technology. In particular, seeding delivery techniques should be examined to improve coverage of storms.

Alberta support is recommended for an international project called Hail swath II. Participants from the United States and Europe would gather in Alberta in 1988, bringing their equipment, to carry out an intensive hailstorm study to address some of the questions that still remain.

Due to the success of the rain augmentation project, it is recommended that the rain research program be expanded.

Funding is also recommended for the SNOWATER project, proposed to adapt snow augmentation technology for use in Alberta.

Operational cloud seeding should be carried out by the private sector. However, every effort should be made to evaluate its effectiveness and a strong link should be maintained between the research and operational compounds of future weather modification programs.

Additional benefits

Weather modification research results in the development of a broad range of expertise and supporting technology which can be applied to other areas of government and private enterprise. The meteorological expertise associated with the weather modification evaluations has been applied to crop yield modelling for Alberta Energy and Natural Resources and in oil production studies for the Alberta Oil Sands technology and Research Authority (AOSTRA). Some of the computer programs have been used by Syncrude in environmental work.

A research aircraft developed jointly by INTERA Technologies and the Alberta Research Council has been used in air pollution studies for Alberta Environment in addition to weather modification research. INTERA has also been successfully marketing the technology and experience gained from its involvement with the weather modification project in the international marketplace. They now have a three-year, $10million weather modification contract with the Greek government. Data collected by the aircraft during the weather modification program will be used by American researchers in a study aimed at revising icing standards for commercial aircraft.

The radar data collected as part of the weather modification program have been analyzed for Alberta Environment to assist in assessment of severe weather events and applied to the development of forecasts of damaging lightning for the Canadian Electrical Association. Radar data are also being used by Alberta Government Telephones to study signal fading during heavy rainfall. These contracts indicate that other Alberta agencies are developing a reliance on the weather radar system that supports weather modification research.

These examples demonstrate how the off shoots of research into weather modification help keep Alberta in the forefront of technology in many related fields.

Conclusion

The potential economic gains to agriculture from cloud seeding are substantial. Furthermore, the Alberta Research Council has developed a world-class team of scientists, and advanced technologies with potential applications in many areas of industry. Therefore, it is recommended that weather modification receive continued support.